How to give notice to vacate in Utah | Advice needed!

[Preston Seo]

Hey guys just a newbie here needing some advice.

So I'm currently under contract for a small multi-family in Davis County, Utah which you Utah folks already know is about 30 minutes north of Salt Lake City. There are currently 3 units that are occupied and one that's vacant (I will be renting this unit out). My wife and I plan to house hack one of the units where the tenant is paying under market value. We've both read Brandon Turner's How to Manage Rental Properties and will be landlording for the first time while we live here. 

They are all on month-to-month contracts and I close next week on the 12th. 

My question is this, and I know it'll seem pretty simple and easy I just want to make sure I go about it the right way.

My understanding is that I can give them a 30 day notice to vacate. 

1. Do you any of you have a form you recommend me using for this?
2. How do I deliver it to them, is it as simple as posting it on their door or hand delivering it to them?
3. I'm confused by some of the stuff I've read that if I don't give it to them the notice by the 1st of the month, and since I will be giving them the notice essentially on the 12th that I will need to give them until the end of next month so until October 31st, is that correct? 

Thanks in advance, we would appreciate any responses!